General instructions Wiring diagrams Torque/angle tightening It is therefore important that the correct types of sea- lant and locking fluids are used on the fasteners where needed, to give a fully acceptable service result. TWD740VE In torque/angle tightening, the fastener is tightened to the specified torque, and tightening then continues th- rough a pre-determined angle. Example: for 90° angle tightening, the fastener is turned a further 1/4 turn in one sequence, after the specified tightening torque has been achieved. In the workshop manual, the relevant chapters contain notes on the preparations used in our engine produc- tion.
In service work, the same preparations or preparations of corresponding properties, but of other makes, shall be used. Lock nuts When sealants and locking fluids are used, it is impor- tant that the surfaces are free from oil, grease, paint and rust-protection, and that they are dry. Dismantled locknuts shall not be re-used, they shall be replaced by new ones, since the locking properties are impaired or lost when the nut is used several times. On locknuts with plastic inserts, such as Nylock®, the tightening torque specified in the table must be reduced if the Nylock® nut has the same nut height as a stan- dard fully metallic hexagonal nut.
Reduce the tightening torque by 25% if the screw dimension is 8 mm or grea- ter. On Nylock ® nuts with higher nut height, where the fully metallic thread is as high as on a standard hexa- gonal nut, use the tightening torques in the table. Always observe the manufacturer’s instructions about temperatures of use, hardening times and other instruc- tions for use of the product. Two basic types of preparation are used on the engine, characteristics are as follows: RTV preparations (Room Temperature Vulcanizing). These are mostly used together with gaskets, such as sealing gasket joints, or are brushed on gaskets.
RTV preparations are fully visible when the component has been disassembled; old RTV compound must be remo- ved before the joint is sealed again. Strength classes Screws and nuts are sub-divided into different strength classes. Classification is indicated by markings on the screw head. Markings of a higher number indicate stronger material. For example, a screw marked 10-9 is stronger than one marked 8-8. For this reason, it is im- portant when fasteners are dismantled, that the screws are put back in the correct places when they are re-in- stalled. When you change screws, please check the spare parts catalogue to ensure that the correct ver- sions are obtained.
The following RTV preparations may be mentioned in the workshop manual: Loctite ® 574, Permatex ® No. 3, Permatex ® No 77. Remove old sealant with denatu- red alcohol in each case. Anaerobic preparations. These preparations harden in the absence of air. These preparations are used when two solid components, such as two cast components, are fitted together without a gasket. Common uses are also to lock and seal plugs, stud threads, taps, oil pressure monitors etc. Hardened anaerobic prepara- tions are glassy and for this reason, the preparations are coloured to make them visible. Hardened anaerobic preparations are highly resistant to degreasers, and old compound can not be removed.
On re-installation, de- grease carefully and then apply new sealant. Sealants Several different types of sealant and locking fluids are used on the engine. The properties of the preparations differ, and they are intended for different strengths of fastener, temperature, resistance to oil and other che- micals, and for the different materials and gap thick- nesses found in the engine. The following anaerobic preparations may be mentio- ned in the workshop manual: Loctite ® 572 (white), Loctite ® 241 (blue). NOTE! Loctite® is a registered trademark belonging to the Loctite Corporation, Permatex® is a registered trademark belonging to the Permatex Corporation.
The positions in the illustration of the EDC system are the same as the positions on the wiring diagram, and show where each component is located on the engine. 46 7